Lactobacillus paracasei subsp. paracasei strain antibacterial against Helicobacter pylori and Escherichia coli 0157:h7

ABSTRACT

The present invention relates to novel lactic microorganism, method for preparation and uses thereof. Particularly, the present invention relates to novel  Lactobacillus paracasei  strain ( Lactobacillus paracasei  subsp.  paracasei  CSK 01) which is prepared by the process comprising the steps: (1) administering lactic bacteria derived from gastric mucus of pig to patients of gastritis and enteritis; (2) separating lactic bacteria from the patients&#39; feces again after their complete recovery; and (3) identifying the bacteria strain by performing 16S rRNA sequencing and RAPD polymerase chain reaction. The  Lactobacillus  strain of the present invention can attach to and proliferate on gastric and intestinal mucosa, resist to acidic and bilious conditions outstandingly and have excellent antibacterial properties. Therefore, the  Lactobacillus  strain and its antibacterial substance can be utilized widely to develop new drugs, functional food, health promoting additives and the like.

CROSS REFERENCE TO RELATED APPLICATIONS

The present application is a section 371 application of PCT International Application No. PCT/KR01/02297, filed Dec. 28, 2001, which claims priority of Korean Application No. 2000/85232, filed Dec. 29, 2000.

TECHNICAL FIELD

The present invention relates to a novel lactic microorganism, its antibacterial substance and methods for preparation thereof. Particularly, the present invention relates to a novel Lactobacillus paracasei strain (Lactobacillus paracasei subsp. paracasei CSK 01) which is prepared by the process comprising the steps: (1) administering lactic bacteria derived from gastric mucus of pig to patients of gastritis and enteritis; (2) separating lactic bacteria from the patients' feces again after their complete recovery; and (3) identifying the bacterial strain by performing 16S rRNA sequencing and RAPD polymerase chain reaction. The Lactobacillus strain of the present invention can attach to and proliferate on gastric and intestinal mucosa, resist to acidic and bilious conditions outstandingly and have excellent antibacterial properties and thus can be utilized widely to develop new drugs, functional food, health promoting additives and the like.

BACKGROUND ART

Generally, Lactobacillus sp. has a high affinity for epithelial cells of alimentary organs which contain a lot of lectin material. Thus, lactic bacteria coming from outer environment to inner body are prone to attach to and proliferate on this region. Also, the lactic bacteria which are settled habitually in the inner body make colonies onto this affiliated surface.

Various kinds of Lactobacillus sp. inhabit aboriginally epithelial cells and make symbiosis to survive mutually, which gives host animals functional benefits consistently. Especially, each species plays a different role and thus has a peculiar function of probiotics, for example A bacterium strain makes colonies, B strain secretes antibacterial substance, C strain secretes highly acidic lactates, D strain helps digestive activities and the like.

Presently, researches about Lactobacillus sp. strains described above have been carried out internationally with a lot of competition and thus the lactic bacteria have been applied to various fields practically. Unfortunately, all the functional Lactobacillus sp. strains obtained from the researches are derived from gut, feces, food, raw food material and so on. Therefore, the Lactobacillus sp. strains are almost killed by gastric acids when prepared with food and eaten although they had an affinity to small and large intestine. Hence the lactic bacteria have problems to be solved for their application and efficacies.

DISCLOSURE OF INVENTION

To overcome the foregoing and other disadvantages, the inventors of the present invention have tried to obtain new lactic bacterial strain which can attach excellently onto gastric and intestinal muci, multiply well and resist to acids, bilis and bacteria. Concretely, we have separated a Lactobacillus paracasei strain from recovered patient's feces after administering lactic bacteria derived from gastric mucous of pig to the patients of gastritis and enteritis and then examined morphological, physiological and cultivational properties of the Lactobacillus paracasei strain. As a result, the bacterial strain of the present invention was confirmed to be a new Lactobacillus paracasei subsp. paracasei strain.

The object of the present invention is to provide a new Lactobacillus paracasei strain which has an antibacterial property. Particularly, the present invention provides Lactobacillus paracasei subsp. paracasei CSK 01 strain (accession number: KCTC 0907 BP) which is antibacterial against Helicobacter pylori and Escherichia coli 0157:H7.

Another object of the present invention is to provide the Lactobacillus paracasei subsp. paracasei CSK 01 strain which is resistant to acids and bilis and can attach to and proliferate on gastric mucus and intestinal mucus.

Another object of the present invention is to provide a process for preparing Lactobacillus paracasei subsp. paracasei strain, which comprises the steps as follows: (1) administering lactic bacteria derived from gastric mucus of pig to the patients of gastritis and enteritis; (2) separating lactic bacteria from the patients' feces again after their complete recovery; and (3) identifying the bacterial strain by performing 16S rRNA sequencing and RAPD polymerase chain reaction.

Another object of the present invention is to provide an antibacterial substance which is separated from Lactobacillus paracasei subsp. paracasei strain and kills or suppresses the proliferation of Helicobacter pylori and Escherichia coli 0157:H7.

Another object of the present invention is to provide food compositions containing the Lactobacillus strain as an effective component, which has functions of preventing and treating gastritis, gastric ulcer and duodenitis induced by Helicobacter pylori and enteritis, colitis and rectitis induced by Escherichia coli and other intestinal pathological bacterial.

The other object of the present invention is to provide pharmaceutical compositions containing the Lactobacillus strain as an effective component, which has functions of preventing and treating gastritis, gastric ulcer and duodenitis induced by Helicobacter pylori and enteritis, colitis and rectitis induced by Escherichia coli and other intestinal pathological bacteria.

Further objects and advantages of the present invention will appear hereinafter.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other objects, features and other advantages of the present invention will be more clearly understood from the following detailed description taken in conjunction with the accompanying drawings, in which;

FIG. 1 a and FIG. 1 b depicts the photograph of Gram-stained lactic bacterium (Lactobacillus paracasei subsp. paracasei CSK 01 strain) in accordance with the present invention;

FIG. 2 depicts the analysis of glycolysis with API KIT 50 CHL in said lactic bacterium of the present invention;

FIG. 3 depicts fatty acid compositions of said lactic bacterium by performing the automated gas chromatography with microbial identification system (Microbial ID. Inc., Newark, Del., USA);

FIG. 4 depicts fatty acid compositions of said lactic bacterium which are analyzed with the automated gas chromatography;

FIG. 5 a, FIG. 5 b, FIG. 5 c and FIG. 5 d depict the analysis of 95 carbon sources with the metabolic fingerprint by using the Biolog GP microplate (Biolog Cat. #1004) of said lactic bacterium;

FIG. 6 depicts the nucleotide sequence (SEQ ID NO:3) of 16S DNA in the lactic bacterium of the present invention;

FIG. 7 depicts the BLAST results which are examined by the 16S rRNA sequencing of said lactic bacterium;

FIG. 8 depicts the PCR result of said lactic bacterium by using specific primers for Lactobacillus paracasei group, which are compared with those of standard Lactobacillus sp.;

FIG. 9 depicts the nucleotide sequence analysis of said lactic bacterium (SEQ ID NO:3) and Lactobacillus paracasei subsp. paracasei JCM 8130;

FIG. 10 depicts the RAPD PCR results of said lactic bacterium and the standard Lactobacillus sp. by using RP primer;

FIG. 11 depicts the RAPD PCR results of said lactic bacterium and the standard Lactobacillus sp. by using CRA25 primer;

FIG. 12 a and FIG. 12 b depicts the properties of said lactic bacterium which can attach to and proliferate on gastric mucus;

FIG. 13 a and FIG. 13 b depicts the properties of said lactic bacterium which can attach to and proliferate on small intestinal mucus;

FIG. 14 depicts the infection of Helicobacter pylori onto the gastric mucus of Balb/c mouse;

FIG. 15 depicts the killing effects of said lactic bacterium upon Helicobacter pylori in infected Balb/c mice;

FIG. 16 depicts the killing effects of antibacterial substance purified from said lactic bacterium upon Helicobacter pylori;

FIG. 17 depicts the infection of Escherichia coli 0157:H7 onto the small intestinal mucus of Balb/c mouse;

FIG. 18 depicts the killing effect of said lactic bacterium upon Escherichia coli 0157:H7 in the infected Balb/c mouse;

FIG. 19 depicts the killing effect upon Escherichia coli in the mixed culture of said lactic bacterium and E. coli 0157:H7;

FIG. 20 depicts the killing effect of the antibacterial substance from said lactic bacterium upon Escherichia coli 0157:H7.

BEST MODE FOR CARRYING OUT THE INVENTION

The present invention provides a Lactobacillus paracasei subsp. paracasei strain which has an excellent antibacterial property. Preferably, the Lactobacillus paracasei subsp. paracasei strain of the present invention is against Helicobacter pylori and Escherichia coli 0157:H7.

In order to obtain the lactic bacterium, the present invention provides a method for preparation which comprises the following steps; (1) administering lactic bacteria derived from porcine gastric mucus to patients of gastritis and enteritis; and (2) separating lactic bacteria again from the patients' feces after they recover completely. Then, the lactic bacterium of the present invention is examined by performing (1) glycolytic analysis with the API KIT 50 CHL, (2) analysis of cellular fatty acid compositions, (3) analysis of carbon sources usages with the metabolic fingerprint and the like. As a result, the lactic bacterium has been identified to be Lactobacillus paracasei subsp. paracasei or Lactobacillus rhamnosus.

In addition, the Lactobacillus sp. strain of the present invention is compared with standard strains by performing the 16S rRNA sequence analysis in order to verify the bacterial strain exactly. Also, the RAPD polymerase chain reaction (PCR) is accomplished to compare the result with that of conventional strains.

Concretely, the strain is confirmed to belong to Lactobacillus paracasei subsp. paracasei with more than 99.9% of accuracy by using the 16S rRNA sequencing and the BLAST analysis of nucleotide sequences. Besides, approximate 300 bp fragments are discovered both in the strain of the present invention and in the standard Lactobacillus paracasei subsp. paracasei similarly when the PCR is performed with specific primers for the Lactobacillus paracasei group, which confirms the CSK 01 strain of the present invention to be a Lactobacillus paracasei subsp. paracasei.

On the other hand, the CSK 01 strain of the present invention shows some differences from Lactobacillus paracasei subsp. paracasei JCM 8130 strain when the results of 16S rDNA sequencing are compared as follows.

Base #861 in CSK 01 strain, G; in JCM 8130 strain, T;

Base #1451 : in CSK 01 strain, A; in JCM 8130 strain,

In addition, when the polymerase chain reaction (PCR) is performed by using RP primer specific for L. paracasei sp., approximate 850 bp fragments are common both in the experimental strain and in the standard strain but other bands are different each other. Then, when the PCR is accomplished by using CRA25 primer specific for L. paracasei sp., about 980 bp and 550 bp fragments are found in the CSK 01 strain, but the standard strain has inconsistent band patterns. Therefore, the CSK 01 strain is clarified to have its specific characteristics.

In order to verify the safety of the bacterial strain, the culture broth of the strain (5×10^(9cfu)/ml) is injected orally into experimental mice (Balb/c) in the amount of 0.3 ml and its twice 0.6 ml, once a day for 10 days and examined the safeties for 2 months. As a result, the experimental group enables health to be sustained in the naked eye and all the organs maintain normal appearances. Precisely, digestive organs including gastric mucus and small intestinal mucus are similar to those of the standard group.

In addition, the present invention provides a Lactobacillus paracasei subsp. paracasei strain which is resistant to acidic conditions.

Concretely, after 10% skim milk is adjusted in the pH range of 1.0˜4.0 by adding HCl, the bacterial strain of the present invention is inoculated and cultivated for 2 days and 4 days respectively. As a result, the strain is confirmed to be resistant to acidic conditions since it can proliferate even in pH 1.5. As a reference, in the CSK 01 strain, less than 10^(1cfu)/ml of cells are separated at pH 1.5 and 10^(4˜5cfu)/ml of cells at pH 2.0.

In addition, the present invention provides a Lactobacillus paracasei subsp. paracasei strain which is resistant to bilis outstandingly.

Concretely, after 10% skim milk is adjusted by adding porcine bilis to become 4.0˜4.5%, the bacterial strain of the present invention is inoculated and cultivated for 2 days and 4 days respectively. As a result, the strain is confirmed to be resistant to bile acidic conditions since it can proliferate even in 4.5%. As a reference, in the CSK 01 strain, less than 10^(2˜3cfu)/ml of cells are separated in the range of 4.0˜4.5%.

In addition, the present invention provides a Lactobacillus paracasei subsp. paracasei strain which can attach and proliferate onto gastric mucus.

Concretely, the experimental mice are administered orally with 0.3 ml of the culture broth once a day for 10 days and after 2 months 1 g of gastric mucus is cut so as to separate 7×10^(8cfu)/g of cells. As a result, the strain is confirmed to attach to and proliferate on gastric mucus innumerably through the electron microscopic observation.

In addition, the present invention provides a Lactobacillus paracasei subsp. paracasei strain which can attach and proliferate onto small intestinal mucus.

Concretely, the experimental mice are administered orally with 0.3 ml (7×10^(9cfu)/ml) of the culture broth once a day for 10 days and after 2 months 1 g of small intestinal mucus is cut so as to separate 7×10^(6cfu)/g of cells. As a result, the strain is confirmed to attach to and proliferate on small intestinal mucus innumerably through the electron microscopic observation.

In addition, the present invention provides a Lactobacillus paracasei subsp. paracasei strain which can kill Helicobacter pyroli.

Concretely, the experimental mice are administered orally with 0.3 ml of Helicobacter pyroli culture broth once a day for 5 days and after 3 days of the infection, re-injected orally with 0.3 ml culture broth of the CSK 01 strain once a day for 10 days. As a result, Helicobacter pyroli is not separated on the gastric mucus and only the CSK 01 strain is recovered. Thus through the electron microscopic observation, the CSK 01 strain is confirmed to be scattered onto the gastric mucus innumerably.

In addition, the present invention provides a Lactobacillus paracasei subsp. paracasei strain which can kill and prevent the proliferation of Escherichia coli.

Concretely, the experimental mice are administered orally with 0.3 ml of E. coli culture broth once a day for 5 days and after 3 days of the infection, re-injected orally with 0.3 ml culture broth of the CSK 01 strain once a day for 10 days. As a result, after 2 months E. coli is not separated on the small intestinal mucus and only the CSK 01 strain is recovered. Thus the strain is confirmed to scatter onto the small intestinal mucus innumerably through the electron microscopic observation.

At that time, Helicobacter pylori is administered in 7×10^(9cfu)/ml of concentration and Escherichia coli 0157:H7 is administered in 3×10^(9cfu)/ml once a day for 5 days and after 3 days, Helicobacter pylori is infected in 7×10^(7cfu)/ml onto gastric mucus of mice and Escherichia coli 0157:H7 is infected in 7×10^(4cfu)/ml onto small intestinal mucus. Then, infected mice are re-injected with the culture broth of the CSK 01 strain in 5×10^(9cfu)/ml once a day for 10 days in 0.3 and after 2 months, only the CSK 01 strain is separated with 7×10^(9cfu)/gl of gastric mucus and 4×10^(6cfu)/g of small intestinal mucus even through Helicobacter pylori and Escherichia coli are not found.

Besides, 2 culture broths of the CSK 01 strain and E. coli are adjusted to the same numbers of cells, inoculated together into 10% skim milk and cultivated for 5 days. As a result, the pattern of cell proliferation is examined that Escherichia coli is killed completely within 70 hours but the CSK 01 strain is not affected any the presence of E. coli so as to proliferate continuously.

Therefore, the strains obtained above are named with Lactobacillus paracasei subsp. paracasei CSK 01 and have been deposited with International Deposit Organization, the Korean Collection for Type Cultures (KCTC) of the Korean Research Institute of Bioscience and Biotechnology (KRIBB), #52, Oun-dong, Yusong-ku, Taejon 305–333, Republic of Korea on Dec. 8, 2000, and identified as KCTC accession numbers, KCTC 0907 BP.

The present invention provides an antibacterial substance which is separated from Lactobacillus paracasei subsp. paracasei-strain and kills or suppresses the proliferation of Helicobacter pylori and Escherichia coli 0157:H7.

Concretely, the culture broth of Helicobacter pylori is smeared on the surface of plate and the disk absorbing the antibacterial substance of the CSK 01 strain is placed onto the center of plate. Then Helicobacter pylori is cultivated in the anaerobic condition and examined to be killed around the disk region. In addition, the CKS 01 strain is cultivated with Escherichia coli in order to investigate the killing effect of E. coli and after 40 hours, E. coli dies remarkably.

The present invention provides food compositions including the Lactobacillus strain or the antibacterial substance as an effective component, which is functional for preventing and treating gastritis, gastric ulcer and duodenitis induced by Helicobacter pylori and enteritis, colitis and rectitis induced by Escherichia coli and other intestinal pathological bacteria.

The present invention provides pharmaceutical compositions including the Lactobacillus strain or the antibacterial substance as an effective component, which is functional for preventing and treating gastritis, gastric ulcer and duodenitis induced by Helicobacter pylori and enteritis, colitis and rectitis induced by Escherichia coli and other intestinal pathological bacterial.

In addition, the bacterial strain and the antibacterial substance of the present invention can be utilized as an effective component of functional food such as various kinds of liquid product from lactic fermented milk, various kinds of powder product from live lactic bacteria and inactivated lactic bacteria, various kinds of ice product adding live lactic bacteria and inactivated lactic bacteria, various cheese products of lactic fermented bacteria, various kinds of beverage adding live lactic bacteria and inactivated lactic bacteria, various kinds of beverage and ice product adding extracts of lactic bacterial extracts and the like.

In addition, the Lactobacillus sp. strain of the present invention and the antibacterial substance can be utilized as an effective component of ointment which can be applied to skin for treating dermatitis related with Escherichia coli. Concretely, various kinds of soluble agent, powder, cream and the like containing live lactic bacteria and/or inactivated lactic bacteria and various kinds of soluble agent, powder, cream and the like containing extracts of the lactic bacteria and/or the purified antibacterial substance.

In addition, the present invention provides pharmaceutical drugs including the Lactobacillus strain or the antibacterial substance as an effective component, which can be applied for preventing and treating gastritis, gastric ulcer and duodenitis induced by Helicobacter pyroli and enteritis, colitis and rectitis induced by Escherichia coli and other intestinal pathological bacteria. Concretely, various kinds of soluble agent, powder, capsule and the like containing live lactic bacteria and/or inactivated lactic bacteria and various kinds of soluble agent, powder, capsule and the like containing extracts of the lactic bacteria and/or the purified antibacterial substance.

The present invention relates to novel Lactobacillus paracasei strain (Lactobacillus paracasei subsp. paracasei CKS 01) which is prepared by the process comprising the steps: (1) separating lactic bacteria from gastric mucosa of pig; (2) administering to gastritis and enteritis patients; and (3) separating from the recovered patients' feces. The Lactobacillus strain of the present invention have been confirmed to attach and proliferate onto gastric and intestinal mucosa and resist to acidic and bilious conditions outstandingly and have excellent antibacterial properties against Helicobacter pylori, Escherichia coli 0157:H7 and the like through identifications of the strain, animal experiments with gastric and small intestinal mucosa, in vivo and in vitro experiments and so on as demonstrated in Examples.

EXAMPLES

Practical and presently preferred embodiments of the present invention are illustrated as shown in the following Examples.

However, it will be appreciated that those skilled in the art, in consideration of this disclosure, may make modifications and improvements within the spirit and scope of the present invention.

Example 1 Separation of Lactic Bacteria from Porcine Stomach

For 10 years (1988˜1998), stomachs were obtained from slaughtered pigs (3,270 heads) in butchery markets located in Pusan, Chinju, Suwon, Jeonju, etc. and stored at 4° C. until it be applied for experimental samples.

Then, 1 g of porcine gastric mucosa was immersed on MRS broth and cultivated at 37° C. for 24 hours. The cultured medium was smeared onto MRS agar plate and left at 37° C. for 3 days. After the incubation, colonies appeared on the agar medium were collected to be examined about bacterial features such as Gram staining pattern, glycolytic capacity and the like as illustrated below. As a result, the bacterium separated above was identified to be a Lactobacillus sp. strain.

Example 2 Purification of Lactic Bacteria from Patients' Feces Administering the Above Lactobacillus sp.

In order to investigate the compatibility and the antibacterial property of lactic bacteria separated in Example 1 to human inner body, 5 patients with chronic gastritis and enteritis were administered. Precisely, 100 ml of the above lactic bacteria was eaten respectively for 2 months in the state of an empty stomach, 30 minutes before rising in the morning and sleeping in the evening. As a result, the progress was improved before and after by injecting for 1 month and after injecting for 2 months, all the patients present in the experiment were recovered.

At this point, lactic bacteria were separated again from 5 administered patients' feces by the procedures described in Example 1 and thus 3˜5×10^(7cfu)/g of cells were obtained. Then the bacterial features were investigated to identify the lactic bacteria comparing with the bacteria separated in Example 1 and identical to that of the administered lactic bacteria separated in Example 1. Hence, the lactic bacteria have been named concisely with CSK 01.

The above lactic bacterium CSK 01 was lyophilized in the state of culture broth adding 10% skim milk, stored at −20° C. and then applied to various experiments for examining bacterial features.

Example 3 Gram Staining of Lactic Bacterium CSK 01

The bacterial features of CSK 01 were examined by using Gram staining. As a result, it was indicated to Gram positive as shown in FIG. 1 a and FIG. 1 b and identified to a rod without spores and in the size of 1.0˜1.5 μm, which was a typical feature indicated in lactic bacillus, Lactobacillus sp.

Then, the lactic bacterium CSK 01 was investigated to elucidate the cultural properties. As a result, it made ash-colored colonies with 2˜3 mm diameter onto MRS agar plate and can be cultivated preferably at 37° C. than at 30° C.

Example 4 Analysis of the CSK 01 Strain with API KIT 50 CHL

The CSK 01 strain was cultivated onto MRS agar plate at 37° C. for 48 hours in the anaerobic condition and suspended with suspension medium in the same turbidity with McFarland 2. Then the cultured cells were inoculated into API 50 CHL strip tube and covered the upper layer with mineral oil in order to examine 49 kinds of glycolytic capacity.

The glycolytic patterns were compared by analyzing the components in the standard Lactobacillus rhamnosus strain and the CSK 01 strain. As a result, in the standard Lactobacillus rhamnosus strain, β-gentiobiose and gluconate were included both in 85% and in the CSK 01 strain, 5% and 45% respectively.

Then, the glycolytic patterns were also examined by analyzing the components in the standard Lactobacillus paracasei subsp. paracasei strain and the CSK 01 strain of the present invention. As a result, in the Lactobacillus paracasei subsp. paracasei strain, 85% of α-methyl-d-glucoside, 99% of amygdaline, 93% of saccharose, 85% of β-gentiobiose and 85% of gluconate were included so as to be determined as positive and in the CSK 01 strain, 40%, 40%, 45%, 50% and 45% were included respectively so as to be decided negative.

In addition, the glycolytic capacities were analyzed by using API identification software program. Consequently, the CSK 01 strain was shown to be similar in the glycolytic pattern to Lactobacillus rhamnosus and Lactobacillus paracasei subsp. paracasei, with 99.2% and 97.1% respectively as illustrated in FIG. 2.

Example 5 Analysis of Cellular Fatty Acid Composition

The CSK 01 strain was cultivated onto MRS agar plate at 37° C. for 48 hours and about 50 mg of culture broth (water-containing weight) was allotted to dry-cleaned teflon-lined screw cap tube with 13×100 mm of size. Then 1 ml of reagent 1 was added for performing the saponification at 100° C. for 30 minutes and 2 ml of reagent 2 was added for performing the methylation at 80° C. for 10 minutes. Again, 1.25 ml of reagent 3 was used to extract fatty acids and left at room temperature. Once 2 layers of reacted mixture were separated, the lower layer was removed and 3 ml of reagent 4 was added so as to wash with base for 5 minutes. Then, about two third of supernatant was moved to septum capped sample vial (12×32 mm; Alltech Associates, Inc., Illinois, USA) and utilized as an experimental sample.

Reagents

(1) Reagent 1 (Saponification Reagent)

150 ml of ion-removed distilled water was mixed with 150 ml of methanol and then 45 g of NaOH (ACS authorization) was added and dissolved completely for the preparation of the saponification reagent.

(2) Reagent 2 (Methylation Reagent)

325 ml of 6.00 N HCl was mixed with 275 ml of methanol (reagent grade) for the preparation of the methylation reagent.

(3) Reagent 3 (Extraction Solvent)

200 ml of hexane (HPLC grade) was mixed with 200 ml of methyl tertiary butyl ether for the preparation of the extraction solvent.

(4) Reagent 4 (Base Wash)

10.8 g of NaOH (ACS authorization) was dissolved with 900 ml of ion-removed distilled water for the preparation of the base wash.

In order to analyze the composition of fatty acids as described in Example 5, Hewlett Packard series II gas chromatography model 6890 (Microbial ID, Inc., Delaware, USA) was used and methyl silica fused silica capillary column (HP 19091B-1020) with 25 ml×0.22 mm×0.33 m of size was exploited for the separation column.

Besides, microbial identification system software (Microbial ID, Inc., Delaware, USA) was utilized for the FAMEs profile. Then, the identification of peaks, the retention time and the area ratio of peaks were measured by comparing with those of standard calibration solution (Microbial ID., Delaware, USA).

At that time, the gas chromatography was performed in the condition as follows: carrier gas, hydrogen; column head pressure, 10 psi; spilt ratio, 100:1; spilt vent, 50 ml/min; septum purge, 5 ml/min; FID hydrogen, 30 ml/min; FID nitrogen, 30 ml/min; FID air, 400 ml/min; initial temperature, 170° C.; program rate, 5° C./min; final temperature, 270° C.; FID temperature, 300° C.; injection port, 250° C.; and injection volume, 2 μl.

As depicted in FIG. 3 and FIG. 4, the results of MIS gas chromatography were shown as followed; major fatty acids, C_(16:0), sum in feature 7 (C_(18:1 w7c)), C_(18:1 w9c), sum in feature 9 (C_(19:0 cyclo w10c)) etc. As a result, the lactic bacterium of the present invention was identified to belong to Lactobacillus sp.

Example 6 BIOLOG Analysis by Metabolic Fingerprint

The CSK 01 strain was cultivated at 28˜35° C. for 24 hours by using Biolog lactic acid bacteria agar (BLA) medium (Cat. #70004) and suspended with 20 ml of 0.85% NaCl so as to be adjusted in 35˜42% range of optical density at 590 nm. Then 150 μl of the culture broth was allotted into 96 wells of Biolog GP microplate (Biolog Cat. #1004) respectively and cultivated at 28˜35° C. for 24 hours.

The reactions were measured with the reader after incubated for 4 and 24 hours independently and analyzed to detect 95 carbon sources usage pattern with the micro release 3.50 software.

The above BIOLOG system was an automated system which can be applied to identify and classify microorganisms by analyzing the 95 carbon sources usage. Especially, it has been exploited to identify and classify lactic bacteria such as Lactobacillus sp., Lactococcus sp. and Pediococcus sp. As described above, the metabolic properties of the CSK 01 strain was characterized by using the carbon sources usage pattern. Consequently, the CSK 01 strain was identified to be Lactobacillus rhamnosus or Lactobacillus paracasei subsp. paracasei as depicted in FIG. 5 a, FIG. 5 b, FIG. 5 c and FIG. 5 d.

Example 7 (7-1) Extraction of Total Genomic DNA

Chromosomal DNA was separated by performing Hunter's method (1985) in the experimental strain and the standard strain. Namely, the preserved strain was inoculated to 10 ml of medium, incubated at 37° C. for 2˜3 days and then cultivated with 100 ml of medium until reached the late exponential stage. About 5 g of bacterial debris was again treated with 10 ml of TE buffer containing 10 mg of lysozyme so as to be suspended for cell lysis at 30° C. for 2˜3 hours.

The lysed cell solution was mixed with 1 ml of 20% SDS slowly and 1.5 ml of 5M NaCl and phenol were added so as to be shaked for 20 minutes slowly. Then it was centrifuged at 3,500 rpm for 10 minutes in order to obtain the supernatant, which was mixed with same volume of chloroform so as to be shaked for 10 minutes slowly and transferred to 100 ml sterilized beaker and mixed with the same volume of isopropanol.

Then, the cell supernatant was left at room temperature for 5 minutes and chromosomal DNA formed between two layers was separated with yellow tips. The resulting DNA was dissolved in the small volume of TE buffer and 20 μg/ml of RNase was added and incubated at 50° C. for 1 hour. Again, 100 μg/ml of protease K, 100 mM of NaCl and 0.4% of SDS were mixed and reacted at 37° C. for 1 hour.

The procedures from the phenol treatment and TE buffer addition were repeated and DNA concentrations were measured with the absorbance at 260 nm.

(7-2) 16S rRNA Sequencing Analysis

Genomic DNA of the experimental strain was assayed quantitatively in the above stage and exploited to perform the polymerase chain reaction (PCR).

At that time, chromosomal DNA of Lactobacillus sp. separated before and demonstrated Table 1 was utilized in 10 μg/ml of concentration as a template for performing the PCR.

TABLE 1 Standard lactic bacteria used for the identification of the CSK 01 strain standard strains accession numbers Lactobacillus paracasei ATCC 11582 Lactobacillus paracasei ATCC 11974 Lactobacillus paracasei ATCC 25302 Lactobacillus paracasei ATCC 25598 Lactobacillus paracasei ATCC 25599 Lactobacillus paracasei ATCC 27092 Lactobacillus paracasei ATCC 27216 Lactobacillus paracasei ATCC 29599 Lactobacillus rhamnosus ATCC 7469  Lactobacillus rhamnosus ATCC 9595  Lactobacillus rhamnosus ATCC 10863 Lactobacillus rhamnosus ATCC 11981 Lactobacillus rhamnosus ATCC 15820 Lactobacillus rhamnosus ATCC 21052

The compositions of PCR reaction mixture were as followed: in 100 μl of the total volume, 1× reaction buffer consisted in 100 mM Tris-HCl (pH 8.3), 500 mM of KCl, 2 mM of MgCl₂, 0.2 mM of dNTP, 200 pmol of sense primer F9 with SEQ ID NO: 1 , 200 pmol of antisense primer 1542R with SEQ ID NO: 2 and 2.5 unit of Taq polymerase as illustrated in Table 2.

TABLE 2 Primers for 16S rRNA sequencing analysis of lactic bacteria in the present invention primers nucleotide sequences 16S Y2 5′-CCCACTGCTGCCTCCCGTAGGAGT-3′ para 5′-CACCGAGATTCAACATGG-3′

The PCR procedures were performed in the reaction condition as followed: denaturation at 95° C. for 5 minutes, again denaturation at 95° C. for 1 minute, annealing at 60° C. for 1 minute, extension at 72° C. for 2 minutes and this process was repeated 30 cycles. Finally, post-extension was proceeded at 72° C. for 10 minutes and the reaction mixture was preserved at 15° C.

The PCR products were separated by using 1% agarose gel electrophoresis and stained with ethidium bromide for the identification.

The PCR product of 1500 bp size was presumed and eluted from the agarose gel by using Qiaquick gel extraction kit (Qiagen) and then cloned into pGEM-T easy vector to construct the LA1500/pGEM-T vector.

Then 16S rRNA sequencing analysis was accomplished by using 16S DNA (position 9-1542) of the CSK 01 strain and PCR. Precisely, the PCR product of about 1500 bp size was cloned into the pGEM-T easy vector and its nucleotide sequence was determined.

In order to determine the nucleotide sequence of the gene, the vector LA1500/pGEM-T was separated by using Wizard™ plus Midipreps DNA Purification System (Promega) and the LA 1500 bp fragment was examined in Bionex Corporation by using automated sequence analyzer (ALFexpress™; Pharmacia Biotech). As a result, the nucleotide sequence of 16S DNA was shown in SEQ ID NO: 3 of Sequence List and FIG. 6.

Example 8 Analysis of Nucleotide Sequence Data with BLAST

The above nucleotide sequence of 16S rRNA was examined and compared with those from already-known Lactobacillus sp. strains and other representative strains belonging to different families by using BLAST program (Altschul et al., 1990; http//www.ncbi.nih.Gov /BLAST) and their homologies were judged.

The family tree was manufactured by exploiting the neighbor-joining method and calculating distance values obtained from the BLAST software.

As a result, the 16S rRNA sequences of the CSK 01 strain were illustrated in FIG. 7 and on the basis of this molecular systematic classification, the CSK 01 strain of the present invention was proved to belong to Lactobacillus casei group. Especially, it showed the highest value of 99.9% homology with that of Lactobacillus paracasei (D79212).

Example 9 Multiplex RAPD PCR Analysis

In order to investigate the experimental strains, the random amplified polymorphic DNA polymerase chain reaction (RAPD PCR) which enabled the typings of Lactobacillus sp. to be analyzed was performed by using arbitrary primers with about 10 bp size.

In addition, the primers which can detect Lactobacillus paracasei specifically were prepared and then used to compare genes of the experimental strains with those of 8 Lactobacillus paracasei strains As demonstrated above, chromosomal DNA of Lactobacillus sp. with 10 μg/μl of concentration separated before was utilized as a template for performing the RAPD-PCR.

The compositions of PCR reaction mixture were as followed: in 50 μl of the total volume, 1×reaction buffer consisting in 100 mM Tris-HCl (pH 8.3), 500 mM of KCl, 3 mM of MgCl₂, 0.2 mM of dNTP, 10 pmol of RP primer with SEQ ID NO: 4, 10 pmol of CRA25 primer with SEQ ID NO: 5 and 1 unit of Taq polymerase as illustrated in Table 3.

TABLE 3 Primers for RAPD analysis of lactic bacteria in the present invention Primers nucleotide sequences RAPD RP 5′-CAGCACCCAC-3′ CRA25 5′-AACGCGCAAC-3′

The PCR procedures were performed in the reaction condition as followed: at 94° C. for 3 minutes, at 45° C. for 45 seconds and at 72° C. for 1 minute (1 cycle); at 94° C. for 45 seconds, at 45° C. for 45 seconds and at 72° C. for 1 minute and this process was repeated 30 cycles; finally at 94° C. for 45 seconds, at 45° C. for 45 seconds and at 72° C. for 5 minutes (1 cycle). Then post-extension was proceeded at 72° C. for 8 minutes and the reaction mixture was preserved at 4° C.

The PCR products were separated by using 1.5% agarose gel electrophoresis and stained with ethidium bromide for typing band patterns.

According to the Ward method (1999), Lactobacillus paracasei group specific primers for detecting the specific sequences were prepared by referring 16S rRNA nucleotide sequences of Lactobacillus paracasei, Lactobacillus rhamnosus and the like.

When the PCR was performed with primers containing unique nucleotide sequences of Lactobacillus paracasei, about 300 bp bands were detected both in the experimental strain and the standard Lactobacillus paracasei strain and the CSK 01 strain of the present invention was identified as a Lactobacillus paracasei subsp. paracasei as depicted in FIG. 8 (lane 1, 17:100 bp DNA ladder; lane 2: the experimental strain; lane 3˜10: Lactobacillus paracasei; lane 11˜16: Lactobacillus rhamnosus).

As illustrated in Example 3˜9, the CSK 01 strain of the present invention was examined for biochemical properties, 16S rRNA sequencing, PCR analysis of identification and the like and as a result, it was proved to be a Lactobacillus paracasei subsp. paracasei.

Example 10 Comparation of DNA Nucleotide Sequences in the CSK 01 Strain and Lactobacillus paracasei Subsp. paracasei

The DNA nucleotide sequences of the CSK 01 strain and JCM 8130 strain were determined as depicted in FIG. 9. As a result, the nucleotide sequences were distinguished in No. 861 and No. 1451: in the CSK 01 strain, G and A respectively and in the JCM 8130 strain, T and G.

Example 11 RAPD PCR with RP Primer in the CSK 01 Strain and Lactobacillus Sp. Strain

When the RAPD PCR was performed with RP primer, about 850 bp bands were detected both in the experimental strain and the standard Lactobacillus paracasei strain, which corresponded to the result obtained from the Ward method (1999). Thus the CSK 01 strain of the present invention was proved to be a Lactobacillus paracasei subsp. paracasei as depicted in FIG. 10 (lane 1, 17:100 bp DNA ladder; lane 2: the experimental strain; lane 3˜10: Lactobacillus paracasei; lane 11˜16: Lactobacillus rhamnosus). However, other bands except the 850 bp band had a disparable pattern from those of the standard strains, which showed the specificity for the CSK 01 strain.

Example 12 RAPD PCR with CRA25 Primer in the CSK 01 Strain and Lactobacillus Sp. Strain

When the RAPD PCR was performed with CRA25 primer, about 980 bp and 550 bp bands were not detected in the standard Lactobacillus paracasei strain, which was different from the CSK 01 strain of the present invention. The above result proved the specificity for the CSK 01 strain as depicted in FIG. 11 (lane 1, 17:100 bp DNA ladder; lane 2: the experimental strain; lane 3˜10: Lactobacillus paracasei; lane 11˜16: Lactobacillus rhamnosus).

As demonstrated in Example 10˜12, in 16S rRNA sequencing and the PCR with RP and CRA25 primers, the CSK 01 strain of the present invention were recognized to have specific properties which did not correspond to those of conventional strains.

Example 13 Safety of the CSK 01 Strain to Balb/c Mouse

In order to examine the safety of the CSK 01 strain, Balb/c mice of 2-week age bred germ-free in Medical Inspection of National Veterinary Science were chosen. Concretely, the CSK 01 strain was inoculated into 10% skim milk (5×10^(9cfu)/ml), administered with the proper amount 0.3 ml and its 2-fold amount 0.6 ml orally once a day for 10 days and after 2 months the safety was measured.

As a result, all the experimental groups injecting 0.3 ml and 0.6 ml of the culture broth were found to survive and be normal with the naked eye.

In the autopsy, the experimental group did not have differences of parenchymal organs (liver, heart, lung, kidney etc.) and digestive organs (stomach, small intestine and large intestine) from the standard group and all the organs were proved normal

The muci of stomach, small intestine, large intestine in the administered group were smeared onto MRS agar plate and cultivated at 37° C. for 48 hours. As illustrated in Table 4, a large number of lactic bacteria were separated from the administered group but no lactic bacteria was detected in the standard group.

TABLE 4 Safty of lactic bacteria in the present invention the administered the standard group group administered amount 0.3, 0.6 — No. of bacteria 5 × 10^(9cfu)/g — No. 20 10 administering 10 days — period results safety 10 days and then — examination after 2 months death — — autopsy *parenchymal *parenchymal organs: normal organs: normal liver liver heart heart lung lung kidney kidney *digestive *digestive organs: normal organs: normal stomach stomach small small  intestine  intestine large large  intestine  intestine recovery innumerable — bacteria in stomach, small and large intestine

Example 14 Resistance to Acids in the CSK 01 Strain of the Present Invention

In order to prepare culture broth, 100 ml of 10% skim milk (pH 6.2) was mixed with 10 N HCl and pH was adjusted to 1.0, 1.5, 2.0, 2.5, 3.0, 3.5, 4.0 respectively. Then 1 ml of the CSK 01 culture solution (5×10^(9cfu)/ml) was inoculated and cultivated for 4 days. The number of bacteria and pH in 2-day and 4-day culture media were measured and the results were summarized in Table 5.

In the case of pH 1.0 medium, the 2-day cultivation changed pH in the range of 1.0˜0.84 and lactic bacteria were not separated.

In the case of pH 1.5 medium, the 2-day cultivation changed pH in the range of 1.5˜2.0 and less than 10^(1cfu)/ml of lactic bacteria were separated.

In the case of pH 2.0 medium, the 2-day cultivation changed pH in the range of 2.2˜2.5 and 10^(4˜5cfu)/ml of lactic bacteria were separated and in the case of pH 2.5 medium, the 2-day cultivation changed pH in the range of 2.7˜3.0 and 10^(3˜6cfu)/ml of lactic bacteria were separated.

In the case of pH 3.0 medium, the 2-day cultivation changed pH in the range of 3.4˜3.6 and 10^(6˜7cfu)/ml of lactic bacteria were separated.

In the case of pH 3.5 medium, the 2-day cultivation changed pH in the range of 3.6˜3.7 and 10^(7˜8cfu)/ml of lactic bacteria were separated.

In the case of pH 4.0 medium, the 2-day cultivation changed pH in the range of 4.5˜5.0 and more than 10^(8cfu)/ml of lactic bacteria were separated.

In the cases of the 4-day cultivation according to pH, the numbers of lactic bacteria were similar to those of the 2-day cultivations.

TABLE 5 Resistance to acids in the CSK 01 strain pH Results (100 ml 2-day culture 4-day culture of 10% No. of No. of skim No. of cells cells milk) samples pH (^(cfu)/ml) PH (^(cfu)/ml) 1.0 5 0.84~1.0  — 0.8~0.9 — 1.5 5 1.5~2.0 10~50 1.3~1.6 10~30 2.0 5 2.2~2.5 10^(4~5) 2.2~2.6 10^(4~5) 2.5 5 2.7~3.0 10^(5~6) 2.7~3.1 10^(5~6) 3.0 5 3.4~3.6 10^(6~7) 3.5~3.6 10^(6~7) 3.5 5 3.6~3.7 10^(7~8) 3.6~4.0 10^(7~8) 4.0 5 4.5~5.0 more 4.6~5.0 more than 10⁸ than 10⁸ Std. 5 5.8~5.9 7 × 10⁹ 5.7~5.9 7 × 10⁹ (6.0)

Example 15 Resistance to Bilis in the CSK 01 Strain

In order to investigate the resistance to bilis of the CSK 01 strain, 100 ml of 10% skim milk was adjusted with porcine bilis (Sig B8631) to 1.0, 1.5, 2.0, 2.5, 3.0, 3.5, 4.0 and 4.5% concentration and then 1 ml (5×10^(9cfu)/ml) of the CSK 01 culture solution was inoculated and cultivated for 2 days and 4 days. Then the culture solution was diluted with MRS broth stored at 4° C. gradually in 10× and 1 ml of diluted solution was smeared onto plates for measuring the cell number.

The number of bacteria was in the range of 10^(7˜9cfu)/ml when bilis was added with 1.0, 1.5, 2.0 and 2.5% respectively, 10^(5˜6cfu)/ml when bilis was added with 3.0 and 3.5% and reduced to less than 10^(2˜3cfu)/ml when bilis was added with 4.0 and 4.5%, which proved the resistance to bilis of the CSK 01 strain.

According to the ratio of bilis amount, the results of 4-day cultivation was similar to those of 2-day cultivation as depicted in Table 6.

TABLE 6 Resistance to bilis of lactic bacteria in the present invention No. of No. of cells (^(cfu)/ml) bilis (%) samples 2-day culture 4-day culture 1.0 5 more than 10⁹ more than 10⁹ 1.5 5 more than 10⁹ more than 10⁹ 2.0 5 10⁸ and more 10⁷ and more 2.5 5 10⁷ and more 10⁶ and more 3.0 5 10⁶ and more 10⁵ and more 3.5 5 10⁵ and more 10⁴ and more 4.0 5 10³ and more 10³ and more 4.5 5 10² and more 10² and more STD 5 more than 5 × 10⁹ more than 5 × 10⁹

Example 16 Attachment to and Proliferation on Gastric Mucus of Balb/c Mice in the CSK 01 Strain

In order to examine the attachment and proliferation of the CSK 01 strain, 20 heads of Balb/c mouse of 2-week age bred germ-free in Medical Inspection of National Veterinary Science were utilized. Concretely, the culture solution of the CSK 01 strain was administered in 0.3 ml amount (7×10^(9cfu)/ml) orally for 10 days once a day after cultivated for 48 hours.

After administered for 2 months, stomachs of mouse were picked out for obtaining gastric mucous and 1 g of gastric mucus was diluted gradually with MRS broth stored at 4° C. in 10×. Then, 1 ml of the diluted solution was smeared onto MRS agar plate and cultivated at 37° C. for 48 hours so as to adjust the number of cells to 7×10^(8cfu)/ml., in order to observe with the scanning electron microscopy (SEM), part of stomach was cut and washed with 1 M phosphate buffered saline (PBS; pH 7.2˜7.4) rapidly and then fixed with 2˜3% glutaraldehyde in 0.1 M PBS, stored at 4° C. for 2˜3 hours, washed with the same buffer, post-fixed with 1% osmium tetroxide in 0.1 ml PBS at 4° C. for 2 hours and then dehydrated with ethanol 50, 70, 80, 90% for 5 minutes and 100% for 20 minutes orderly.

Then, as a substituting agent, isoamyl acetate was used, dried with the critical point dryer and coated with ions in order to be observed with the electron microscopy (Hitach, S-570). As a result, the CSK 01 strain was confirmed to attach to and proliferate on gastric mucus as depicted in FIG. 12 a and FIG. 12 b.

Example 17 Attachment to and Proliferation on Small Intestinal Mucus of Balb/c Mice in the CSK 01 Strain

In order to investigate the attachment to and proliferation on small intestinal mucus, the CSK 01 strain was separated from gastric mucous as described above and observed with the electron microscopy.

As a result, the CSK 01 strain was obtained with the number of 3×10^(6cfu) and confirmed to attach to and proliferate on gastric mucus by the electron microscopic observation as depicted in FIG. 13 a and FIG. 13 b.

As demonstrated in Example 13˜17, the CSK 01 strain of the present invention was proved to be resistant to acids and bilis and attach to and proliferate on gastric mucus and intestinal mucus of Balb/c mice.

Example 18 Infectivity of Helicobacter pyroli Against Balb/c Mice

Helicobacter pylori was obtained from patients and stored in Department of Microbiology, Bokeum hospital, Pusan. Precisely, Helicobacter pylori 121 strain was lotted out.

The Helicobacter pylori was cultivated in the anaerobic condition (gas packed jar) with Mueller—Hinton broth (MHB) containing 10% calf serum for 4 days and then smeared onto 10% sheep blood medium to be incubated again for 4 days. Thus, it was identified to be Gram-positive, flexible and spiral and harvested by using 10% Mueller—Hinton broth stored at 4° C. and glass beads. Then the cells were administered orally to Balb/c mice once a day for 5 days in 0.3 ml of culture solution with 2×10^(9cfu)/ml and after 3 days stomachs of Balb/c mice were cut.

1 g of gastric mucus was diluted with MHB stored at 4° C. in 10× gradually and 1 ml of diluted solution was smeared onto 10% sheep blood medium. As a result, 7×10^(7cfu)/g of bacteria were separated.

In addition, tissues treated as above was observed with the electron microscopy and examined to be infected with a large number of bacteria as shown in FIG. 14.

Example 19 Killing effect of the CSK 01 Strain Against Helicobacter pylori Infected in Balb/c Mice

Balb/c mice infected with Helicobacter pylori were administered orally with the culture broth of the CSK 01 strain (5×10^(9cfu)/ml) once a day in 0.3 ml amount for 10 days and after 2 months, gastric mucus was investigated to detect Helicobacter pylori by using the previously described method. As result, Helicobacter pylori was not found and the CSK 01 strain was detected with 1×10^(9cfu)/g.

In addition, the gastric mucus treated above was observed with the electron microscopy and examined to be infected with a large number of the administered bacteria but Helicobacter pylori was not found as shown in FIG. 15.

Example 20 Killing Effect of Antibacterial Substance from the CSK 01 Strain against Helicobacter pyroli

The culture broth of the CSK 01 strain was cultivated with 10% skim milk at 37° C. for 48 hours and 100 ml of the culture broth was allotted in 50 ml amount to the sonicator and maintained at 4° C. for 30 seconds. This procedure was repeated 5 times with sonicating (Sonical material, Vc×375) and then centrifuged at 10,000 g for 30 minutes so as to recover the supernatant.

Then, 80% saturated solution of ammonium sulfate was added to float cells, left at 4° C. for 24 hours and centrifuged so as to recover the precipitates. Then, the cells were diluted 2 times with sterilized distilled water stored at 4° C. and poured onto dialysis membrane (PGC 29-0593-37, MWCO, 10K) so as to be dialyzed at 4° C. for 48 hours by using distilled water.

Then the purified solution prepared above was allotted again with saturated 40% ammonium sulfate solution, left at 4° C. for 24 hours and centrifuged at 10,000 G for recovering the supernatant. Again it was diluted 2 times with the same process and freeze-dried at 4° C. for 48 hours.

The lyophilized antibacterial substance of the CSK 01 strain was re-diluted 2 times after 10% skim milk was added, sonicated and centrifuged at 10,000 G to obtain supernatants.

The culture broth of Helicobacter pylori was smeared onto Mueller—Hinton agar containing 10% calf serum and a disk absorbing the antibacterial substance of the present invention was placed in the center of culture plate and incubated in the anaerobic condition. As a result the inhibition range was measured and the proliferation of Helicobacter pylori was verified to suppresed completely around the disk as depicted in FIG. 16.

Example 21 Infectivity of Escherichia coli 0157:H7 Against Intestinal Mucus of Balb/c Mice

Escherichia coli 0157/H7 strain was allotted from Microbiology Lab., Department of Veterinary Science, Kyungsang University.

Escherichia coli 0157/H7 strain was inoculated onto BHI broth, cultivated at 37° C. for 18 hours and harvested by adding sterilized physiological saline on the agar plate and using glass beads. Then the number of cells was calculated by diluting gradually with the sterilized physiological saline in 10× and to be 3×10^(9cfu)/ml.

The culture medium was administered orally into Balb/c mice in 0.3 ml amount once a day for 5 days and after 3 days, small intestinal mucus was cut partially.

1 g of small intestinal mucus was diluted gradually in 10× by adding sterilized physiological saline and then 1 ml of diluted solution was smeared onto 7% sheep blood medium and cultivated at 37° C. for 18 hours. As a result, cells in 6×10^(5cfu)/g was separated and confirmed to be Gram negative, rod shaped, to react positive against E. coli 0157:H7 antiserum and the like so as to be a Escherichia coli.

On the other hand, the small intestinal mucus was observed with the electron microscopy to find the survival of Escherichia coli and a large number of Escherichia coli was confirmed to attach to and proliferate on the mucus as shown in FIG. 17.

Example 22 Killing Effect of the CSK 01 Strain Against Escherichia coli 0157:H7 Infected Balb/c Mice

Balb/c mice infected with Escherichia coli 0157:H7 were administered orally with the culture broth of the CSK 01 strain (5×10^(9cfu)/ml) once a day for 10 days and after 2 months, small intestinal mucus was investigated to detect Escherichia coli 0157:H7 with the electron microscopy.

Concretely, 1 g of small intestinal mucus was diluted gradually in 10× by adding sterilized physiological saline and 1 ml of the diluted solution was smeared onto BHI agar plate and cultivated at 37° C. for 20 hours in order to examine the survival of bacteria. As a result, Escherichia coli 0157:H7 was not found and the CSK 01 strain was detected in 4×10^(5cfu)/g when the same procedure with the above was performed.

Meanwhile, the small intestinal mucus treated above was observed with the electron microscopy again. As a result, it was verified to be infected only with a large number of the administered the CSK 01 strain and Escherichia coli 0157:H7 was not found at all as shown in FIG. 18.

Example 23 Killing Effect against Escherichia coli in the Mixed Culture of the CSK 01 Strain and Escherichia coli 0157:H7

1 ml of the CSK 01 strain (2˜6×10^(8cfu)) in MRS broth and 1 ml of E. coli (2˜6×10^(8cfu)) in BHI broth were adjusted to have the same concentrations of cells. Both were inoculated into 10% skim milk together, cultivated at 37° C. for 5 days and after 20 hours the numbers of the CSK 01 cell and E. coli were calculated.

Concretely, the CSK 01 strain was estimated by using MRS agar medium and E. coli, by using MacConkey agar medium and 1 ml of the culture broths were smeared onto agar plates respectively to get the cell numbers.

As a result, the number of E. coli was examined to reduce from after 30 hours, then most of cells were killed after 40 hours and finally all the cells died killed after 70 hours as depicted FIG. 19.

Contrarily, the CSK 01 strain was not varied in the number of cells (4×10^(9cfu)/ml) even after 70 hours.

Example 24 Killing Effect of Antibacterial Substance from the CSK 01 Strain Against Escherichia coli

The antibacterial substance was purified, precipitated with saturated ammonium sulfate solution, freeze-dried as described above, diluted to 300 mg/ml and absorbed into a disk in 20 μl amount.

E. coli cells cultivated in BHI broth were smeared onto the tryptic soy agar plate and the disk-absorbing the antibacterial substance was left in the center of plate, then incubated at 37° C. for 24 hours. As a result, it was confirmed that the proliferation of E. coli was inhibited around the disk as depicted in FIG. 20.

As demonstrated in Example 18˜24, the CSK 01 strain of the present invention was proved to have the antibacterial properties for killing Helicobacter pyroli inducing gastritis of Balb/c mice and Escherichia coli inducing enteritis.

INDUSTRIAL APPLICABILITY

As illustrated above, the present invention relates to novel Lactobacillus paracasei strain (Lactobacillus paracasei subsp. paracasei CSK 0) which is prepared by the process; separating lactic bacteria from gastric mucosa; administering them to gastritis and enteritis patients; and separating again from the recovered patients' feces. The Lactobacillus strain of the present invention can attach to and proliferate on gastric and intestinal mucosa, resist to acidic and bilious conditions outstandingly and have excellent antibacterial properties, especially against Helicobacter pylori. Therefore, the Lactobacillus strain and its antibacterial substance are expected to be applied to various fields efficiently.

Those skilled in the art will appreciate that the conceptions and specific embodiments disclosed in the foregoing description may be readily utilized as a basis for modifying or designing other embodiments for carrying out the same purposes of the present invention. Those skilled in the art will also appreciate that such equivalent embodiments do not depart from the spirit and scope of the invention as set forth in the appended claims. 

1. Lactobacillus paracasei subsp. paracasei CSK 01 strain having an antibacterial property wherein said Lactobacillus paracasei subsp. paracesi is the deposited strain of Accession Number: KCTC 0907 BP.
 2. The Lactobacillus paracasei subsp. paracasei CSK 01 strain of claim 1, wherein the antibacterial property is against Helicobacter pylori and Escherichia coli 0157:H7.
 3. The Lactobacillus paracasei subsp. paracasei CSK 01 strain of claim 1, being resistant to acids and bilis and which can attach to and proliferate on gastric mucus and intestinal mucus.
 4. A food composition comprising the Lactobacillus strain of claim 1 as an effective component in combination with a food, the Lactobacillus strain having functions of preventing and treating gastritis, gastric ulcer and duodenitis induced by Helicobacter pylori and enteritis, colitis and rectitis induced by Escherichia coli and other intestinal pathological bacteria.
 5. A pharmaceutical composition comprising the Lactobacillus strain of claim 1 as an effective component in combination with a pharmaceutical carrier, the Lactobacillus strain having functions of preventing and treating gastritis, gastric ulcer and duodenitis induced by Helicobacter pylori and enteritis, colitis and rectitis induced by Escherichia coli and other intestinal pathological bacteria. 